Conventional electric water deicers are used to keep areas of livestock water tanks and ponds free from ice during winter months. One type of deicer is a floating deicer in which a buoyant member such as a buoyant ring is attached to a heating element so that the deicer may float on the surface of the water. Another type of deicer is a sinking deicer that is configured to lay at the bottom of a tank or pond, or on a metal guard submerged in the tank. A drain plug deicer is yet another type of deicer that is mounted through a drain hole of a tank and operates similar to a sinking deicer.
As water cools, it becomes denser until it reaches a temperature of approximately 4° C., at which point it begins to expand again. The expansion causes the coolest water to rise to the surface of a tank where it freezes at 0° C. Likewise, as water is heated above 4° C. by a deicer, the warm water rises to the surface. The continual supply of warm water provided by a deicer prevents the surface of the water from freezing over. Such a deicing effect may be accomplished by continually operating a heater in water. Deicers, on the other hand, typically include a temperature sensor (e.g., a thermostat) that detects when the water temperature rises above a freezing point. A typical deicer then deactivates a heating element when water is not susceptible to freezing in order to conserve energy. When the temperature sensor detects that the water temperature is at or close to the freezing point, the deicer re-activates the heating element in order to heat the water.
A floating deicer only heats proximate a water surface. The warmer water forms a layer on top of the colder water at the bottom of the tank or pond. As such, the floating deicer operates as if it is only heating a smaller body of water at the top of the tank or pond, as opposed to the entire tank or pond. A floating deicer may come into contact with livestock that drink from the tank. Horses, in particular, are known to bite objects and lift them out of tanks. Additionally, an animal may be burned if it contacts a hot heating element.
A sinking deicer is submerged in a water tank or pond and is, therefore, beyond the reach of most animals. Due to the fact that the sinking deicer lies at the bottom of the water receptacle, however, the sinking deicer is configured to heat the entire body of water, instead of just the top layer that is susceptible to freezing. As the sinking deicer heats the water, the warmer water flows to the surface thereby displacing the colder water downward. Thus, in order for the temperature sensor within the deicer to detect the presence of warmed water, the heater remains activated until the entire volume of water above the deicer is warmed water. As such, a sinking deicer is typically activated much longer than a floating deicer. Consequently, a typical sinking deicer requires more energy to operate than a typical floating deicer.
Additionally, as a tank of water cools, the water contained within the tank may form a significant temperature gradient between the top and the bottom of the tank. Because water is at its densest at 4° C., the dense water remains at the bottom of the tank as the surface water cools. Thus, the surface of the water may be at 0° C. while the deicer at the bottom of the tank detects a water temperature of 4° C. This situation is exacerbated by the fact that the heat in a still tank travels via conduction, which may be a slow process.
In order to overcome a delayed heating trigger, typical sinking deicers are configured to activate heating elements at around 5°-6° C. As water is heated, the warmed water flows upward displacing colder water downward. As such, the temperature gradient may be more pronounced with a difference of over 10° C. between the top and bottom of the tank. For example, a sinking deicer set to activate at 11° C. may deactivate while the surface temperature is actually around 21° C. or higher. Thus, typical sinking deicers waste energy due to the fact that they usually heat water long after the threat of freezing has been overcome.
Typical drain plug deicers provide the same advantages and disadvantages of sinking deicers discussed above. Unlike a sinking deicer, however, a typical drain plug deicer includes an electrical cord that is disposed completely outside of the fluid receptacle. Much like a sinking deicer, however, a typical drain plug deicer excessively heats the water within the receptacle, thereby wasting energy.
As discussed above, sinking and drain plug deicers are less efficient than floating deicers. Sinking and drain plus deicers are, however, safer to use in the presence of livestock and other animals.